1. Field of the Invention
The invention relates generally to the field of communication systems for vehicles such as automobiles and trucks, and more particularly, to communicatively coupling devices within the vehicle.
2. Description of the Related Art
Microprocessor technology has greatly improved the efficiency, reliability and safety of the automobile. Microprocessor devices have enabled airbags, anti-lock brakes, traction control, adaptive suspension and power train control just to name a few of the areas where processing technology has literally transformed the automobile. These systems, first provided by manufacturers only on the most expensive luxury and performance automobiles, are now common and even standard equipment on the most affordable economy models. Soon, control-by-wire applications will become equally commonplace. For example, throttle-by-wire has been successfully implemented on a number of vehicle platforms. Steer-by-wire and brake-by-wire applications are not far behind. Alternative fuel vehicles, including fuel cell vehicles, electric and hybrid vehicles will require still more sophisticated control applications, and hence still more processing capability.
The automobile is simultaneously being enhanced by information technology. Satellite navigation systems, voice and data communications, and vehicle telemetry systems inform the driver, entertain the passengers and monitor vehicle performance. These systems can provide driving directions, identify points of interest along the driver""s route, remotely diagnose and/or predict vehicle problems, unlock the doors, disable the vehicle if stolen or summon emergency personnel in the event of an accident.
The growing amount and level of sophistication of vehicle oriented information technology presents the challenge to the automotive engineer to implement and integrate these technologies with existing and emerging vehicle systems in an efficient manner. Current design philosophy centers on the incorporation of one or more vehicle communication bus structures for interconnecting the various control elements, sensors, actuators and the like within the vehicle. The design of these bus structures is often driven by compliance with governmental regulations such as second-generation on-board diagnostics (OBD-II) and federal motor vehicle safety standards (FMVSS). These structures offer limited ability to adapt new technology to the vehicle. Moreover, given the typical four-year design cycle and ten-year life cycle of an automobile, the technology within a vehicle may become significantly obsolete even before the vehicle is brought to market, and the bus architecture leaves the owner little ability to adapt new technology to the vehicle. Notwithstanding these limitations, the bus architecture offers a generally reliable, relatively fast platform for linking electronic devices and systems within the vehicle.
To link vehicle system technologies with vehicle information technologies, there has been proposed to incorporate a network architecture within the vehicle. For example, published Patent Cooperation Treaty (PCT) application number WO 00/77620 A2 describes an architecture based on the Ethernet wherein devices within the vehicle are coupled to the network. This publication describes a network including a cable backbone to which the devices are coupled and a network utility for controlling communications between the devices over the network. Important to note is that the proposed network does not integrate the vehicle systems, but instead is adapted to provide a platform for adding information technologies, such as pagers, personal digital assistants, navigations, etc. technologies to the vehicle. The power train, suspension, braking and airbag systems, as examples, utilize a vehicle bus for data communications, and these systems operate autonomously of the network described in the publication. A bridge or gateway is provide to couple the vehicle bus to the network as a device or client allowing data sharing between the bus and the network, but the data communication needs of the vehicle systems are not serviced by the network. A reason that these systems are designed to operate autonomously of the described network is that they have time critical, system critical data requirements that cannot be met by the network structure described. Additionally, the network described in the publication suffers from numerous single points of failure, such as if the cable backbone is disrupted or the network utility fails.
Thus there is a need for an architecture for automotive electronic systems that facilitates the efficient, reliable integration of in-vehicle electronic technologies and plug-and-play upgradeability.